The energy for operating a power supply system is supplied by various different types of power plants. Most of the power plants, such as, for example, nuclear power plants, coal-fired power plants, gas-fired power plants, wind energy plants, biogas plants or solar power plants, are hereby only energy generators for feeding energy into to non-local power supply systems. Non-local power supply systems are transmission networks, for example, such as operated in Germany, for example, by Amprion, 50 Hertz, Tennet and TransnetEnBW. These transmission networks are part of the European grid. As pure energy generators, the above-mentioned power plants cannot absorb and store any excess energy from the power supply system, if required. In contrast, energy storages can be used to absorb and emit energy to a power supply system. Energy storages are, for example, central energy storages, such as pumped storage plants or decentralized energy storages, such as batteries or flywheel storages, for example. The pumped storage plants represent energy storages, which are largely independent on the weather and which are thus on principle always available. Central energy storages are generally designed for a large capacity. To provide control energy for the non-local power supply systems, they are suitable for displaying a corresponding effect in the non-local power supply systems due to the available output. Depending on the overall size, pumped storage power plants can have an output of several 100 MW and more, wherein the generators, however, are mostly designed to produce electricity under full load and are thus able to promptly use the entire output of the pumped storage plant with a corresponding efficiency. This mode of operation is not suitable to stabilize or to improve an electricity demand, which is rather negligible as compared to the capacity of the pumped storage power plant.
Centrally used battery-storage systems are being designed with the goal of realizing a pilot operation for grid-stabilizing (localized) tasks (control energy). The ones planned to date, however, do not fulfill any localized tasks. However, due to their immanent correlations between output, capacity and deterioration, battery storages are, on principle, not well suited for such applications with a plurality of load cycles per day and degrade quickly due to temperature influences, system failures and operating errors. Battery storages are thus very maintenance-intensive. Due to their high fire and chemical risk, battery storages also represent a danger to the environment and/or water, which require an enormous protection effort.
On principle, decentralized energy storages are optimized for the stabilization of the local power requirement and are not designed and qualified for supplying control energy to support the non-local power supply system. Such plants cannot contribute in meeting the demand of all power supply systems. An interconnection of the decentralized storages to form a non-local and locally acting plant does not currently take place.
It would thus be desirable to have an energy storage, which is effective, environmentally safe and which can be operated easily, comprising a large capacity, which makes it possible to be able to simultaneously attain an improvement of local grid quality and the supply guarantee for non-local power supply systems, as required, and which can thus be operated as energy storage system with a sufficient effect for both purposes.